Dolby Labs

10 responses to “Dolby Labs”

1. 

   !MimosaMicheMichelle!

   Jul 27, 2010 at 9:00 pm

   It makes one appreciate the technology which brings us increased pleasure in entertainment!
   And, of course, you look cool with these 3D glasses! Bonjour Steve!

   Reply
2. 

   P^2 – Paul

   Jul 27, 2010 at 9:40 pm

   Interesting. The eye is pretty non-linear for colo[u]r perception though. A 20 nm shift in the deep red is almost imperceptible, and you probably wouldn’t object to it in the blue. But shift green/yellow light 20 nm and you’ll be reaching for the "hue" control on the projector. There must be something a little more sophisticated than that happening.

   I wonder why they don’t use circular polarization? Easy to make left or right handed, orientation agnostic, and really cheap. Getting around a patent or something?

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3. 

   heet_myser

   Jul 27, 2010 at 9:46 pm

   I staunchly refuse — refuse, I say! — to upgrade from 5.1 surround.

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4. 

   photon~wave

   Jul 28, 2010 at 4:39 am

   [http://www.flickr.com/photos/imager] Circular polarization system is used (and patented) by RealD Cinema. The dichroic filters in the Dolby 3D glasses are more expensive and fragile, but no special silver screen is needed for it to work. The patent application, which includes a good summary of methods for 3D stereoscopic projection, could be seen here.

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5. 

   P^2 – Paul

   Jul 28, 2010 at 10:48 am

   Ah. That explains all. Thanks!

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6. 

   j_silla

   Jul 31, 2010 at 12:29 pm

   Seems that there is more then enough material to read on this http://www.jdsu.com/search/search.cfm?q=3d+ If you are interested in this more, you might know that there is an Estonian firm, that is making 3D film cameras, As known David Cameron has got one as well. http://www.siliconimaging.com/DigitalCinema/News/PR_01_07_10_Int...
   hei.eas.ee/index.php?option=com_content&view=article&…

   http://www.digitalsputnik.com/page4/page4.html

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7. 

   TomiTapio

   Aug 13, 2010 at 11:24 am

   Oh wow, a filter that can frequency-shift, wtf.

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8. 

   P^2 – Paul

   Aug 13, 2010 at 1:47 pm

   No wtf about it. Example: A low-pass filter shifts the center frequency of a signal to lower frequencies. A high-pass the opposite. A linear filter does this by reducing (absorbing) power at some frequencies, shifting the mean frequency. Obviously, you can’t do this with monochromatic signals. However, a non-linear filter can shift monochromatic signals, and losslessly too, through parametric oscillation. A (real, commercially available, I have one) light source based on this principle accepts light at 532 nm, and outputs three beams: one at (typically) 700 nm, the other at 2200nm, and some fraction of the original 532 nm. It is even tunable. Aside from minor reflection losses, the process is 100% efficient.

   However, the filters described above are not of this type: they are ordinary (but sophisticated, multiband, sharp cut-off) linear filters.

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9. 

   _Jim1

   Jul 15, 2013 at 3:24 pm

   [http://www.flickr.com/photos/imager] Paul, you have the EE in me shaking my head; via the process of heterodyning one can literally shift frequencies, strictly speaking, filters (linear, time invariant) however, have no such ability … group delay, yes (unequal time delay of various frequencies BUT no shifting!)

   Shifting requires non-linear mixing techniques utilizing a second ‘tone’ or carrier to accomplish the ‘offset’. Now, this is all applicable to electronics, as I am far less well-versed in optics on this subject!

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10. 

    P^2 – Paul

    Jul 15, 2013 at 5:29 pm

    [http://www.flickr.com/photos/59592866@N06] In the narrowband case, what you say is correct – it’s impossible to shift (significantly) the frequency with a linear filter. In a wideband signal, however, you will significantly shift the mean frequency if you filter out (for example) the high frequencies.

    In the optical case, if a band-limited white input (say) 500-540 nm (mean of 520 nm) is filtered by a filter rejecting 520nm and longer wavelengths, the mean of the remaining signal will be 510 nm.

    Even in a the non-linear heterodyne mixing case, the mechanism responsible for the bulk of the *mean* frequency shift is the filter that rejects the output frequencies that are not of interest. (e.g. an FM radio signal at 100.1 MHz mixes with a LO of 110.8 MHz to produce a (useful) IF at 10.7 MHz, plus other outputs at 210.9 and spurious 110.8 and 100.1. Only the 10.7 is used: the higher frequencies are absorbed by a filter.)

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